Residual stresses in alumina scales. Experiments, modeling, and stress-relaxation phenomena
The stresses generated in alumina scales during different oxidation steps control the protective character of such scales and their lifetime. Laboratory and industrial Fe-Cr-Al alloys, differing by their impurity content and preparation, and for which the oxidation kinetics were previously characterized, were studied here to experimentally determine or theoretically calculate the stress level in the alumina scales. The experiments were performed by X-ray diffraction (XRD) at room temperature, using the sin{sup 2} {Psi} method. The oxide-stress level was correlated with many parameters, such as the scale microstructure and morphology, the nature of the substrate, the substrate and oxide thickness, the oxide grain size, the cooling rate, etc. A numerical elasto-vis-coplastic model was developed to calculate the thermal stresses and to point out the effect of the relaxation phenomena either during cooling or during isothermal treatment after oxidation. The results obtained by the elasto-vis-coplastic model are in good agreement with the experimental ones.
- Research Organization:
- Univ. Paris Sud, Orsay (FR)
- OSTI ID:
- 20015575
- Journal Information:
- Oxidation of Metals, Vol. 53, Issue 1-2; Other Information: PBD: Feb 2000; ISSN 0030-770X
- Country of Publication:
- United States
- Language:
- English
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